MikeOH

Forgetting the IP violations, I believe YOU will need to perform and submit test data to obtain a "Gorwim" TSO. You can't just say, "Well, I built mine exactly like Garmin, so I can use their TSO."

Sigh... my point is if you get a 337 approved, the install is legal.

Hmm, seems to me that if an A&P inspects and determines the part to be airworthy, signs off on a 337 (if he thinks that's what it requires)...then it is no longer an unapproved part.

You got it! "Do NOT adversely affect the performance of the equipment or article into ...." I am in no way convinced that meeting FCC Part 15 regs will assure that the item does not interfere with avionics. But, to your point, I am not convinced that everything sold as TSO/aviation approved is guaranteed not to interfere...even though it should be!

Ah, you just want to rant about how "unfair" the existing regulations are, and how illogical. Hey, I agree with you. That doesn't change the fact that they are what they are; they do NOT have to make sense to be enforceable. If you are seriously asking someone to explain FAA reasoning,...well good luck with that. I thought you wanted to know how to perform a legal install. You can install what you want yourself and hope the IA at your next annual doesn't care...and any future buyer's pre-buy inspector. You can pay a willing A&P to install and sign off whatever junk you can buy cheap off ebay. That will be legal. You can pay a willing A&P to install and sign off an approved USB. That would be legal. You can buy a cheap USB cigar lighter USB and plug it in. That would be legal.

What are you trying to accomplish here? Cliffy has provided a rather thorough explanation of how parts on an aircraft are determined to be acceptable. You appear to be playing semantic games with 'proof' that will be acceptable to you. I'll make it easy: you are NOT going to find any single reg that directly states, "Thou shall NOT use any item on an aircraft that is not TSO, PMA, or STC." Happy?

Which one of the multitude of specifications you linked is the one that defines what is required for a USB adaptor to meet aviation EMI/RFI requirements?

The issue is if the non aviation approved 'auxiliary USB power socket' introduces EMI/RFI into the nav/comm system. The device in the OPs post may, or may not, cause an interference issue. Practically speaking, I'd rather NOT buy an unknown part, pay an A&P to install and complete whatever paperwork he deems required, and THEN find out the device does, in fact, cause interference. Much easier to buy a USB adaptor that plugs into the existing cigar lighter socket. No A&P or approval required. If there's an interference issue, just plug in another brand. Rinse and repeat as required; the things are low cost. I was lucky. The PO of my plane had already found one that plugged in and doesn't cause interference

I learned to fly in 1977, in California. C-150 was $10.50/hr wet; instructor $5/hr; Call it $16/hr total. California minimum wage was $2.65. So, about 6 hours work = 1 hour flying. Today, in California, that same C-150 (and, quite possible that it is the SAME plane!) is $100/hr, instructor is $60/hr; $160/hr total. Minimum wage is now $12/hr. Thus, 13 hours work = 1 hour flying. DOUBLE the work. To me, that is a SIGNIFICANT difference. Not to mention that, IMHO, it takes MORE hours today. Whether that's due to more FAA regs before solo, or litigation concerns, or whatever.

I find 1/4 travel to result in too high of an after start rpm. 1/4 travel for prime, but I back the throttle down before cranking to a position where I get around 1200 rpm after start. Additionally, I find that varying the number of seconds I prime dependent on OAT to be important. Sorry, but following the POH (open to full rich and then to return to idle cutoff) lacks that necessary detail.

Uh, NO I am not. Rather than follow presently accepted witchcraft I am going to go with Lycoming's advice (posted by G Miller earlier in the thread): From a Lycoming Publication..... In our many years of building engines, the engines have benefited during continuous operation by keeping CHT below 400 F in order to achieve best life and wear of the powerplant. In general, it would be normal during all year operations, in climb and cruise to see head temperatures in the range of 350 F to 435 F. I have no problem keeping CHTs in the mid-350s during cruise, and will continue to do so. I am, however, not going to sweat a 10-15 minute climb to altitude in the summer with a 410F CHT. Nevertheless, I am going to look into my full power fuel flow as it does seem low both anecdotally, and from Savvy cohort data.

Nice summary, Skip. That's pretty much the conclusion I was coming to. Aluminum has no fatigue life limit, so ANY repetitive stress will eventually cause a fatigue failure. It's worse, for just the reason you stated, at elevated temps. The question becomes one of time (how many repetitive stress events, i.e. combustion events) and temperature curve to failure. Based on material FACTS, it's pretty clear that 25% of aluminum's room temp strength is gone at only 300F; yet, no one worries about that. And, at 400F 75% of that yield strength is gone! Yet, 'keeping it below' 400F is somehow considered 'safe.' As you say, the engineers have designed to account for this. I think your previous comment about CHTs being the latest LOP and shock cooling sacred cow is spot on

When I was shopping, specifically for Mooneys, I briefly considered M20As. Others will likely disagree, but I was just too uncomfortable with finding a knowledgeable mechanic that I could trust for a wood wing. Yes, aluminum corrodes and wood rots, so it's not like aluminum is 'better.' But, it's just not common any more and that spar is over 60 years old and has seen who knows what conditions over that time span. The prices just weren't that much lower to justify the risk. Good luck!

@Ragsf15e Thanks for the reminder about fuel flow. I do need to pursue it. What I think that really means is pulling the fuel servo and sending it in...not wild about that...$$$$

Oh, plenty of INTEREST, just no SAY in what is getting purchased.....I'm pretty sure the guy writing the check is sitting in the back!

@Ragsf15e As far as EGTs go, I've been a believer (perhaps incorrectly?), that the absolute number is kind of irrelevant plane-to-plane due to installation differences. Yes, I have looked at sea-level full rich fuel flow; mine runs about 16.5 gph. Some have told me that is low, but I specifically had my mechanic look into it at my recent (Jan 2020) annual and he was not concerned. It is my understanding that the RSA fuel servo needs to be sent in to change that setting; it's NOT field adjustable.

@Ragsf15e Yes; that hot with 120 mph climb, cowl flaps full open, WOT, full rich (KPOC is 1000'), 2600-2650 rpm. My EGTs run about 1330, and that's what I lean for at high DA. Not stock inlet; I'm not certain which mod mine is. OAT definitely makes a difference. This time of year, 60-75 OAT, no problem (hotter than yours, but not over 390). Summer time when OAT is 85-100, is where I have an issue.

LOL! Boy, ain't that the truth! I've been stressing over my above 400F CHTs since I've owned my plane. Thanks to this thread I'm going to relax a bit and accept my 410F climb CHTs and mid-300s cruise CHTs. It was really bugging me to pull back power on hot day climbs just to keep CHTs under 400.

Hmm, yet, supposedly, Mike Busch is the one who said 450 during break-in is okay?!? Which is full circle back to my original question: How is 450 degrees during break-in any less damaging than 450 during climb out? Yes, I get it that higher temps should be avoided...but, by that logic and the strength of aluminum vs. temp graphs, we should be operating below 300 F (approx. 25% loss of strength). At least, with my new baffling, I don't see over 410F on climb-out anymore. Not that it applies to our Lycomings, but Skip's reference to P&W R1820 shows 450F in climb out is ok.

Thank you! Now, THAT is an answer. And, it is a big relief; I've never seen 435, even in climb out on a hot day.

That's exactly what I see, as well; and, run WOT, LOP. It's climb out on a hot day that is my issue.

Familiar with 1 through 13...doesn't really address my confusion, I'm afraid. Not worried about 'wearing a step' due to not changing RPM. Trying to understand how much time at elevated temps is going to appreciably affect cylinder life. Put another way: How many hours at elevated (400s kind of temp) does it take before a cylinder is broken in? How are those hours any different, as far as affecting longevity, than operating at elevated temperatures after break-in? I've fought moderately high temps since I bought my M20F over two years ago. #2 would run up to 425 on climb out on a hot day. With new baffles that number is down to just over 400 when it's hot out. I'll pull power to keep the temps down, but someday I may need full-power and backing off won't be an option. The way everyone talks, it sounds like running at 425 for even a few minutes is HORRIFIC I'm NOT talking about cruising for hours at high CHTs. Now, I'm beginning to wonder how true that really is... if running for HOURS at 450 during break-in is okay and, presumably, doesn't destroy cylinder life, why is running 400-410 for a 15 minute climb on the occasional hot day such a problem?

The "#3 runs very hot.." thread has me wondering... There was a reference in that thread to Mike Busch saying 450 was actually okay during break-in! My understanding was that anything much over 400 needs to be dealt with ASAP as some large percentage of the aluminum's strength is gone. The needing to deal with it ASAP suggests this very damaging to the cylinder; like it's going to take hundreds of hours off the life of the cylinder. Seems there is evidence that this is true: cylinders that are run hot don't last. So, how is it that high temps during break-in are okay? Seems to me that if it doesn't break-in over only a few hours, you are taking a TON of life off your brand new cylinder. Okay, expert metallurgists, explain this to me, please.

Ideally, you want the filter as close to the source of noise as possible/practical. Much better to kill the noise at its source than filter out its effects at the susceptible components. Mid-wire may well work, as it did for Richard, but technically the wire from the beacon to the filter is still radiating noise.

Rags, While I hadn't noticed any symptoms, I had this happen to ONE stud on my #2 cylinder. I spotted it after pulling the cowling for a routine check (I try and do this every 25 hours). Please check that the studs are properly torqued in the head; in my case the threads in the aluminum head were stripped! That's WHY the nuts backed off; the studs would NOT support the tension for the required torque. I had to heli-coil the head to fix the issue.